This invention relates to the art of packaging integrated circuit chips; and more particularly to connectors for replaceably securing integrated circuit packages to a printed circuit board.
Integrated circuit packages comprise an integrated circuit chip that has been encapsulated in a protective material such as plastic or ceramic. These packages can be either leaded or leadless. In the former, electrical conductors extend from the encapsulant as a means for sending signals to and receiving signals from the chip; whereas in the latter, that means is provided by electrical pads that lie flush with the encapsulant.
In the prior art, these packages have been connected to printed circuit boards in both an irreplaceable and a replaceable fashion. Typically, an irreplaceable connection is made by soldering the package directly to the printed circuit board; whereas a replaceable connection is made by soldering a connector to the printed circuit board and inserting the integrated circuit package into the connector in a solderless fashion.
Electrical conductors are provided in the socket to make electrical connections between the printed circuit board and the leads or pads in the integrated circuit package. However, to make those connections reliable, the electrical conductors in the socket and the corresponding leads or pads in the package must be pressed together with a certain minimal amount of force.
In the past, a typical integrated circuit package had only 16 leads or pads, and so the total compressive force that was required to make reliable contacts between a connector and that package was only five pounds. However, with the advent of large scale integrated circuits, the number of transistors that can be fabricated on a single chip has passed 100,000. But to fully utilize this capability, more leads or pads are required to input and output signals to the chip. Depending on the irregularity with which these transistors are interconnected, over 100 input/output signals may be required.
But as the number of leads or pads on an integrated circuit package increases, the minimum compressive force that is required between the package and the conductors in the connector also increases. For example, a 128 lead package would typically require a minimum force of forty-two pounds. But connectors generally are quite small (e.g. 2.75 cm.times.2.75 cm). And so the forty-two pound compressive force must be supplied by one's fingers, which is difficult to do with prior art connectors.
Accordingly, a primary object of this invention is to provide an improved connector for use with an integrated circuit package.
Another object of the invention is to provide a connector that latches to and compresses the leads/pads of an integrated circuit package with a mechanical advantage of greater than one.